1. Field of the Invention
The present invention relates to an apparatus to produce a self-piercing and clinch nut and a method for producing a self-piercing and clinch nut.
2. Discussion of the Background
Japanese Examined Patent Publication No. 08-029392 and Japanese Patent No. 5325934 disclose an apparatus to produce a self-piercing and clinch nut by forging.
A self-piercing and clinch nut is secured on a parent material, which is a material such as a steel sheet to accept the self-piercing and clinch nut, in the following manner. First, a hole is punched in the parent material by a pilot portion of the self-piercing and clinch nut. At the same time, part of the parent material is deformed to fill a gap between the pilot portion and a surrounding wall (rib) of the self-piercing and clinch nut. Thus, the parent material is clinched by the nut, and the nut is firmly secured on the parent material. This indicates that dimensional precision of the pilot portion and the surrounding wall of the nut is a critical factor that determines how firmly the self-piercing and clinch nut is secured.